Insights / Bank Statement Loan Expense Ratio: 50% Standard vs 20% With CPA Letter
September 25, 2026
Bank Statement Loan Expense Ratio: 50% Standard vs 20% With CPA Letter
Lenders underwriting a bank statement loan default to a 50% expense ratio, meaning they treat half of your business deposits as expenses and only count the other half as income. A letter from your CPA confirming your actual expense structure can lower that ratio to 20%, which often means significantly more qualifying income for high-deposit, low-expense businesses.
That 30-point swing between 50% and 20% isn't a rounding error. For a service business or consultancy running a lot of revenue through the bank with genuinely low overhead, the standard 50% haircut can wipe out enough income to sink a loan approval. The CPA letter exists specifically to fix that mismatch between what the lender assumes and what your business actually spends.
Why do bank statement loans assume a 50% expense ratio in the first place?
Bank statement loans exist for self-employed borrowers who can't (or don't want to) document income through tax returns, so the lender needs another way to estimate what the business actually nets. Instead of underwriting a full profit-and-loss statement, most programs apply a flat, conservative assumption: half of what hits the business bank account went out the door in expenses, payroll, rent, inventory, whatever it takes to run the business. The other half is treated as usable income and averaged over the statement period, typically 12 or 24 months.
It's a blunt instrument by design. The lender doesn't know your actual margins, so it picks a number that's safe across a wide range of business types. A restaurant with real food and labor costs might spend close to that 50% or more. A one-person consulting shop invoicing clients for advisory work might spend nowhere near it.
What does the CPA letter actually need to say?
The letter has to state two specific things: that the CPA has reviewed the business's expense structure, and that the stated expense factor (the percentage the borrower is asking the lender to use instead of 50%) is accurate for that business. A generic letter that just says "I'm this borrower's accountant" or verifies they're self-employed doesn't do the job. The letter needs to speak directly to the expense ratio itself and put the CPA's name behind a specific number, typically down around 20%.
This is why the letter can't come from a bookkeeper who's never reviewed the full financial picture, and it can't be boilerplate. It's a professional opinion, in writing, that the lender's default assumption is too conservative for this particular business.
When is it actually worth getting one?
The CPA letter route makes sense for high-deposit, low-expense businesses, the classic examples being consultants and other service-based operations where the owner isn't carrying much in the way of materials, inventory, or heavy overhead. If most of what comes in stays in, the 50% standard ratio is costing you qualifying income for no good reason.
It's usually not worth the trouble for businesses where the real expense ratio is close to 50% anyway, or higher. If your CPA can't credibly support a 20% figure, ordering the letter doesn't help and can slow the file down. This is a targeted fix for a specific mismatch, not a step every bank statement borrower should take by default.
How much difference does it actually make to qualifying income?
The honest answer is it depends entirely on your deposit volume and your actual expense structure, since neither of those numbers is something we can generalize here. What's consistent is the direction: moving from a 50% assumed expense ratio to a 20% one roughly doubles the share of your deposits treated as income, which flows straight through to your debt-to-income ratio and how much loan you qualify for.
| Factor | Standard treatment (no CPA letter) | With a qualifying CPA letter |
|---|---|---|
| Assumed expense ratio | 50% of gross deposits | Can drop to 20% of gross deposits |
| Effect on qualifying income | More deposits treated as expense, lower usable income | More deposits treated as income, higher usable income |
| Documentation needed | 12 or 24 months of business bank statements | Same statements, plus a CPA letter addressing the expense factor |
| Best fit | Businesses with real overhead near or above 50% | High-deposit, low-expense businesses like consultants and service providers |
| Underwriting flexibility | Set by program guidelines, little room to negotiate | Requires lender to accept the CPA's stated expense factor |
Does this apply to personal bank statement loans too, or just business accounts?
The 50% expense ratio and the CPA letter option are specific to business bank statement programs, where deposits represent business revenue that includes both income and overhead mixed together. Personal bank statement loans work differently: the lender is generally looking at deposits into a personal account and doesn't apply the same expense-ratio assumption, since there's no business overhead to net out. If you're not sure which category your file falls into, that's a conversation for your loan officer before the statements even get ordered.
A real scenario
Jesse worked with a self-employed consultant whose business bank statements showed strong, consistent deposits every month. Run through the standard 50% expense ratio, the qualifying income came in low enough to threaten the approval, even though the business itself was healthy and the owner's actual overhead was minimal. The fix was a CPA letter: the borrower's accountant reviewed the business's real expense structure, confirmed it ran far leaner than the standard assumption, and put a specific expense factor in writing. With that letter in the file, the lender used the lower ratio instead of the default 50%, and the qualifying income moved enough to get the loan back on track. No new job, no new deposits, just a more accurate picture of what the business actually spent.
What if my CPA won't sign a letter like this?
Some CPAs are reluctant to put a specific expense factor in writing because it puts their name on a number a lender will rely on. If yours isn't comfortable doing that, the loan defaults back to the standard 50% ratio, and the conversation shifts to whether a different program fits better, sometimes DSCR-based financing if the deposits are tied to a rental or investment property, or a conventional or FHA path if tax returns actually support the income. Programs like these live under the broader Non-QM pillar, which covers bank statement, DSCR, and other self-employed income options side by side, so it's worth reviewing the full menu rather than assuming one path is the only option.
How does this affect what loan amount I can afford?
Qualifying income drives your debt-to-income ratio, which drives your maximum loan amount, so a lower expense ratio (and higher qualifying income) generally means more purchasing power. Before ordering a CPA letter or pulling statements, running your numbers through an affordability calculator gives you a rough sense of what's at stake between the 50% and 20% scenarios, even though the calculator won't replace an actual underwriting review.
If you're a consultant, freelancer, or service business owner whose bank statements look a lot better than your tax returns, the expense ratio question is worth raising early, not after a preliminary approval comes back lower than expected. Talk to Jesse Gonzalez or reach out to the team before you order statements, so the CPA letter conversation happens on the front end of the file instead of as a scramble in the middle of underwriting.
Frequently asked questions
What is the standard expense ratio on a bank statement loan?
The standard expense ratio is 50%, meaning the lender assumes half of your business's bank deposits went toward business expenses and only counts the remaining half as qualifying income.
How much can a CPA letter lower the expense ratio?
A qualifying CPA letter can lower the assumed expense ratio to 20%, which means significantly more of your business deposits count toward qualifying income compared to the standard 50% assumption.
What exactly does the CPA letter need to state?
The letter needs to say the CPA has reviewed the business's expense structure and that the stated expense factor being requested (typically around 20%) is accurate for that business; a generic letter confirming self-employment isn't enough.
Who benefits most from getting a CPA letter?
High-deposit, low-expense businesses benefit most, particularly consultants and other service-based businesses where actual overhead is far below the standard 50% assumption.
Is a CPA letter worth getting for every self-employed borrower?
No, it only makes sense when your actual expense ratio is genuinely lower than 50%; if your business carries real overhead close to or above that level, the letter won't change your qualifying income and isn't worth the extra step.
Does the 50% expense ratio apply to personal bank statement loans too?
No, the 50% expense ratio and the CPA letter option apply to business bank statement programs where deposits mix income and overhead; personal bank statement loans generally don't apply the same expense-ratio assumption.
What happens if my CPA won't provide the letter?
The loan defaults back to the standard 50% expense ratio, and it's worth discussing other options, such as programs under the Non-QM umbrella or a conventional or FHA path if your tax returns support the income instead.
How many months of bank statements does a lender review for this program?
Most bank statement programs review either 12 or 24 months of business bank statements to calculate an average monthly deposit figure before applying the expense ratio.
Reviewed by Jesse Gonzalez, NMLS #278103
This article is for general information only and is not a loan approval, rate quote, or financial advice. Program guidelines change and every file is different, so talk to a licensed loan officer about your scenario. True Blue Lending Corporation, NMLS #2380218. Equal Housing Opportunity.